The present invention relates to an arrangement of lubricant oil passages in an automatic transmission.
Japanese Patent Application Publication No. H10 (1998)-339368 shows an automatic transmission including a clutch drum formed, by press forming, with splines including raised portions and recessed portions, a rotational speed measuring device configured to measure a rotational speed of the clutch drum in accordance with an outer surface of splines of the clutch drum with the raised portions and the recessed portions, and oil holes each formed in one of the raised portions raised radially outwards, and arranged to discharge oil in the clutch drum. The rotational speed measuring device of this document is located at a position being different from positions of the oil holes in the axial direction of the clutch drum.